Year Percent 1996 4.10749 1997 7.45057 1998 9.05211 1999 9.98159 2000 7.47178 2001 6.70793 2002 6.10955 2003 3.55589 2004 2.63559 2005 2.55663 2006 2.11954 2007 2.24087 2008 1.98112 2009 2.33841 2010 2.33694 2011 3.89142 2012 3.64215 2013 3.15737 2014 4.16105 2015 3.81223 2016 3.87534